1. Marijuana is far less addictive than alcohol.

Dependence: How difficult it is for the user to quit, the relapse rate, the percentage of people who eventually become dependent, the rating users give their own need for the substance and the degree to which the substance will be used in the face of evidence that it causes harm.

2. Deaths from the two substances. There are hundreds of alcohol overdose deaths each year, yet there has never been a marijuana overdose death in history. The consumption of alcohol is also the direct cause of tens of thousands of deaths in the U.S. each year.

Excessive alcohol consumption is the third leading preventable cause of death in the United States (1) and is associated with multiple adverse health consequences, including liver cirrhosis, various cancers, unintentional injuries, and violence.

The CDC has no reports of “marijuana-induced deaths.” (In reality, there may be 2-5 deaths each year attributed to marijuana, but this article -- http://bbsnews.net/bw2005-02-01.html -- describes how these are actually deaths attributable to other causes but “blamed” on marijuana due to the way the data is collected.)

3. Alcohol is one of the most toxic drugs, and using just 10 times what one would use to get the desired effect can lead to death. Marijuana is one of – if not the – least toxic drugs, requiring thousands times the dose one would use to get the desired effect to lead to death. This “thousands times” is actually theoretical, since there has never been a recorded case of marijuana overdose.

The most toxic recreational drugs, such as GHB (gamma-hydroxybutyrate) and heroin, have a lethal dose less than 10 times their typical effective dose. The largest cluster of substances has a lethal dose that is 10 to 20 times the effective dose: These include cocaine, MDMA (methylenedioxymethamphetamine, often called "ecstasy") and alcohol. A less toxic group of substances, requiring 20 to 80 times the effective dose to cause death, include Rohypnol (flunitrazepam or "roofies") and mescaline (peyote cactus). The least physiologically toxic substances, those requiring 100 to 1,000 times the effective dose to cause death, include psilocybin mushrooms and marijuana, when ingested. I've found no published cases in the English language that document deaths from smoked marijuana, so the actual lethal dose is a mystery. My surmise is that smoking marijuana is more risky than eating it but still safer than getting drunk.

Despite the health risks and social costs, consciousness-altering chemicals have been used for centuries in almost all cultures. So it would be unrealistic to expect that all types of recreational drug use will suddenly cease. Self-management of these substances is extremely difficult, yet modern Western societies have not, in general, developed positive, socially sanctioned rituals as a means of regulating the use of some of the less hazardous recreational drugs. I would argue that we need to do that.

4. Long-term marijuana use is far less harmful than long-term alcohol use.

There is little evidence, however, that long-term cannabis use causes permanent cognitive impairment, nor is there is any clear cause and effect relationship to explain the psychosocial associations.

There are some physical health risks, particularly the possibility of damage to the airways in cannabis smokers. Overall, by comparison with other drugs used mainly for ‘recreational’ purposes, cannabis could be rated to be a relatively safe drug.

5. The United Kingdom's Science and Technology Select Committee considers alcohol far more harmful than marijuana.

The committee commissioned an assessment of 20 legal and illegal stimulants in order to bring some logic to the country’s drug classification. Based on this study, they made recommendations to the government, including a recommendation that alcohol be considered among the most harmful drugs. Cannabis was considered significantly less harmful. (See chart below.) As you can see in the chart below, cannabis was recently rescheduled in the UK and is now a Class C substance (with A being the most harmful).

6. There has never been a documented case of lung cancer in a marijuana-only smoker, and recent studies find that marijuana use is not associated with any type of cancer. The same cannot be said for alcohol, which has been found to contribute to a variety of long-term negative health effects, including cancers and cirrhosis of the liver.

It could be interesting to note in the chart the difference between what people usually consider the most likely serious harms associated with marijuana and alcohol. While there has never been a documented case of lung cancer in a marijuana-only smoker, there are clearly thousands of deaths by liver disease directly associated with alcohol – 12,360 in 2003, to be exact. [See, http://www.cdc.gov/nchs/fastats/alcohol.htm . Note also on this page that “alcoholic liver disease” is a separate category from “alcohol-induced deaths, excluding accidents and homicides.” Thus the 20,687 cited in #2 (as “deaths from alcohol consumption” could easily be 33,047.]

The largest study of its kind has unexpectedly concluded that smoking marijuana, even regularly and heavily, does not lead to lung cancer.

The new findings "were against our expectations," said Donald Tashkin of the University of California at Los Angeles, a pulmonologist who has studied marijuana for 30 years.

"We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use," he said. "What we found instead was no association at all, and even a suggestion of some protective effect."

Federal health and drug enforcement officials have widely used Tashkin's previous work on marijuana to make the case that the drug is dangerous. Tashkin said that while he still believes marijuana is potentially harmful, its cancer-causing effects appear to be of less concern than previously thought.

Earlier work established that marijuana does contain cancer-causing chemicals as potentially harmful as those in tobacco, he said. However, marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming cancerous.

Tashkin's study, funded by the National Institutes of Health's National Institute on Drug Abuse, involved 1,200 people in Los Angeles who had lung, neck or head cancer and an additional 1,040 people without cancer matched by age, sex and neighborhood.

They were all asked about their lifetime use of marijuana, tobacco and alcohol. The heaviest marijuana smokers had lighted up more than 22,000 times, while moderately heavy usage was defined as smoking 11,000 to 22,000 marijuana cigarettes. Tashkin found that even the very heavy marijuana smokers showed no increased incidence of the three cancers studied.

"This is the largest case-control study ever done, and everyone had to fill out a very extensive questionnaire about marijuana use," he said. "Bias can creep into any research, but we controlled for as many confounding factors as we could, and so I believe these results have real meaning."

Tashkin's group at the David Geffen School of Medicine at UCLA had hypothesized that marijuana would raise the risk of cancer on the basis of earlier small human studies, lab studies of animals, and the fact that marijuana users inhale more deeply and generally hold smoke in their lungs longer than tobacco smokers -- exposing them to the dangerous chemicals for a longer time. In addition, Tashkin said, previous studies found that marijuana tar has 50 percent higher concentrations of chemicals linked to cancer than tobacco cigarette tar.

While no association between marijuana smoking and cancer was found, the study findings, presented to the American Thoracic Society International Conference this week, did find a 20-fold increase in lung cancer among people who smoked two or more packs of cigarettes a day.

The study was limited to people younger than 60 because those older than that were generally not exposed to marijuana in their youth, when it is most often tried.

7. Studies find alcohol use contributes to the likelihood of domestic violence and sexual assault and marijuana use does not.

Of the psychoactive substances examined, among individuals who were chronic partner abusers, the use of alcohol and cocaine was associated with significant increases in the daily likelihood of male-to-female physical aggression; cannabis and opiates were not significantly associated with an increased likelihood of male partner violence.

…the odds of any male-to-female physical aggression were more than 8 times (11 times) higher on days when men drank than on days of no alcohol consumption. The odds of severe male-to-female physical aggression were more than 11 times (11 times) higher on days of men’s drinking than on days of no drinking. Moreover, in both samples, over 60% of all episodes occurred within 2 hours of drinking by the male partner. (page 1557)

Source: Fals-Stewart , William, James Golden, Julie A. Schumacher. Journal of Addictive Behaviors. 28, pages 1555-1574. Intimate partner violence and substance use: A longitudinal day-to-day examination. Research Institute on Addictions, University at Buffalo, State University of New York

8. Studies find alcohol use contributes to aggressive behavior and acts of violence, whereas marijuana use reduces the likelihood of violent behavior.

Alcohol is clearly the drug with the most evidence to support a direct intoxication-violence relationship.

11. Alcohol use is prevalent in cases of sexual assault and date rape on college campuses. Marijuana use is not considered a contributing factor in cases of sexual assault and date rape, as judged by the lack of discussion of marijuana in sexual assault and date rape educational materials.

Comparisons between alcohol and marijuana with respect to sexual assault are very difficult. This is because it does not appear as if marijuana is a significant contributing factor. The best way to "prove" this is through observation that many organizations dedicated to studying and educating about sexual assault do not list marijuana as a substance associated with incidents. Here is a good example from the Rape, Abuse & Incest National Network: http://www.rainn.org/types-of-assault/sexual-assault/drug-facilitated-assault.html

Note their description of alcohol: "Alcohol is the most commonly used chemical in drug facilitated sexual assault. In large part this is due to the fact that alcohol is easily accessible and a chemical that many people use in social interactions." Given the fact that marijuana is also "easily accessible" and used widely in "social interactions," it is quite telling that marijuana is not even listed at all on this "Drug Facilitated Assault" page.

Another example: A Web site sponsored by the U.S. Dept. of Health and Human Services lists alcohol, but not marijuana, as putting a person at risk for unwanted or risky sexual activity: http://www.4woman.gov/faq/rohypnol.htm#5